The invention relates to a method for the estimating of the residual service life of an apparatus which is subject to wear during operation. The invention further relates to the use of such a method for service planning.
For many apparatuses, such as turbines or jet engines of airplanes, the wear of or at important components is the main reason for the limited service life, with “service life” usually meaning the period of time or the operating period between two standard audits. Wear can manifest itself by changes in the mechanical properties of components, which is due, for example, to friction, heat or fatigue. These changes at the components also bring about a changed behavior of the whole apparatus with unchanged operating conditions. It is therefore necessary to carry out audits or service work on the apparatus at regular intervals.
Methods known today for the planning of such service work are usually based on purely time-defined service intervals; that is, a fixed time interval is set for the service life between two audits. For safety reasons, very conservative approximations are assumed for the service life already used up. It is clear that such purely time-supported methods do not result in an optimum utilization of the possibilities of the apparatus, because the wear which actually occurred, which is also influenced by the specific operating conditions and environmental conditions, is not taken into account. To increase the efficiency of utilization of such apparatuses, for example airplane engines, it is therefore desirable to have a more realistic estimate available for the residual service life, in which the actual operating conditions and environmental conditions are also taken into account in order thus to make possible a more efficient and more economic service planning.